World’s first floating bridge to be built in Bjørnafjorden

On the west coast of Norway, the world’s first suspension bridge on floating foundations is being projected, combining bridge and offshore technology.

Architects from different offices are working on developing solutions for the mainland connections along the long stretch of coast between Kristiansand and Trondheim. There are eight fiords that today are crossed by ferry, and the 1100km route could reduce the driving time between the two cities by seven hours.

A tubular bridge that delves beneath the surface may be the future crossing of Sognefjord. Image: Sweco.

Combination of offshore and bridge technology in Bjørnafjorden

The combination of water depths of up to 550 meters and a total length of about 5km makes it impossible to build conventional types of bridges in Bjørnafjord.

Two concepts they are working on are a conventional floating bridge and a tubular, submerse bridge rooted in panto collector. The third solution is a combination of the suspension bridge and the floating bridge.

“Floating bridges and submerged tubular bridges are the only appropriate options when making a road over such a broad fjord area,” says project manager Mathias Eidem in NPRA.

If the suspension bridge is elected, it will be the first of its type ever brought up anywhere in the world. The floating foundations are those normally used in the offshore industry.

“This is a totally new concept, which consists of a suspension bridge standing on floating structures,” says Svein Erik Jakobsen, head of the bridge division at Aas-Jakobsen AS. “In this way we bring together different communities from both offshore and bridge and develop the concept together.”

The total area to be connected at the end of the project.

The project has worked with a similar solution for the crossing of the Sognefjord. How much the bridge will cost is still uncertain.

“We are working our way towards a cost estimate now and cannot say anything specific about how much the bridge will cost. But there is no cheap solution, we can say already,” Jakobsen adds.